1. Field of the Invention
The present invention relates to a system, method and user equipment for managing the floor for a multimedia communication service in a Push-To-Talk (PTT) over Cellular (PoC) system, in which a PoC session is independently opened for various types of media supported by a client for selective transmission according to media types. More particularly, the present invention relates to a system, method and user equipment for managing the floor for a multimedia communication service in a PoC system, in which an independent PoC session is opened for a media type supported by a first responding client under a multimedia PoC environment, so as to allow selective media transmission according to the types of media provided by clients responding after the first responding client.
2. Description of the Related Art
Significant development of mobile communication technologies and the expansion of communication networks have led to the provision of various services and applications which use cellular phones. Also, user interests have expanded to services such as location, multimedia and Push To Talk (PTT) services, beyond the basic communication service. Particularly, the PTT service supports various supplementary functions such as instant messenger and status display, as well as group and voice communication which have been provided by an existing radio transmitter or a trunked radio system (TRS).
Standardization of a PTT over Cellular (PoC) service which employs such a PTT function in a mobile communication network is actively proceeding. One unique feature of the PoC service, which draws a distinction between the PoC service and the existing mobile communication service, is that a user can participate in a plurality of PoC sessions, thereby enabling use of a communication service while moving among the PoC sessions. A requirement that a user must be able to use communication service while moving among a plurality of PoC sessions is specified in the Open Mobile Alliance (OMA), which is a forum for specifying mobile communications services.
Meanwhile, the PoC V2.0 system supports a PoC multimedia communication service. To this end, the PoC V2.0 system defines new types of multimedia such as video, audio and text, in addition to voice.
It is also possible in the current PoC system to display a multi-stream (e.g., video or image) due to the improvement of performance of user equipments.
As a result, when the conventional PoC V1.0-based session open method and/or system is used in the PoC V2.0 system, there may be limitations in providing various multimedia services supported in the PoC V2.0, and a long time is required to open a session.